The development of methods of rapidly identifying and characterizing biological materials, such as microorganisms and cells, is major focus of academic and industrial research. The need for such methods has been felt in the health, laboratory, and environmental industries. In medicine, for example, the exponential rise in antibiotic-resistant bacteria and emerging viral disease has caused a crisis in the health-care and food industries. As a result, there has been a continued pressure to find new, reliable, and rapid means of characterizing pathological and disease-causing organisms. Similarly, the threats of biological warfare and terrorist activities which have been felt world-wide has caused an escalated search for ways of identifying putative biological agents, especially in the field, in airports, and in other public areas.
Coupled with the need for advanced biological agent detection methods has been an escalating effort in the sequencing of DNA from all types of organisms and identifying expressed genes. The complete genomic sequences of a number of microorganisms had been completed. The availability of such information about genome and proteome of whole organisms is an important reservoir to be exploited for identifying and characterizing unknown and known organisms.